1. Field of the Invention
The present invention relates to forming polyurethanes. More specifically the present invention relates to forming a medium-to-high durometer, non-porous, and thermoformable polyurethane using bio-renewable and recycled ingredients.
2. Background of the Invention
The state of the art for constructing surfaces such as bars, countertops, etc., has, for decades, involved acrylics. From the time that DUPONT developed their acrylic-based CORIAN material until today, acrylics and acrylic/polyester blends have been in dominant use for such applications. The benefits of such composite materials are numerous: acrylic/polyester countertops integrate well with other surfaces and structures without forming lips or seams when fabricated, and are non-porous, therefore being suitable for sterile applications such as hospitals.
However, several major limitations exist for these materials. Specifically, they are extremely brittle, crack and scratch very easily, and are fairly expensive and heavy. It takes a substantial amount of labor to transport these products to their desired locations, while their brittleness only adds to the overall costs of using them as interior surfaces.
Another popular composite solid uses a polyurethane resin as its base. Polyurethane is typically manufactured with two groups of at least bifunctional substances as reactants: compounds with isocyanate groups, and compounds with active hydrogen atoms. The physical and chemical character, structure, and molecular size of these compounds influence the polymerization reaction, as well as ease of processing and final physical properties of the finished polyurethane. In addition, additives such as catalysts, surfactants, blowing agents, cross linkers, flame retardants, light stabilizers, anti-settling agents, and fillers are used to control and modify the reaction process and performance characteristics of the polymer.
However, existing polyurethanes are extremely susceptible to water. Specifically, any moisture content influences the reaction and creates bubbles of CO2 gas. This results in foaming within the material, making it porous. The porosity automatically disqualifies a polyurethane from being used in sterile applications as well as kitchen countertops, sinks, etc.
The use of polyols derived from vegetable oils to make polyurethane products began attracting attention around 2004. The rising costs of petrochemical feedstocks and an enhanced public desire for environmentally friendly green products have created a demand for these materials. Memory foam mattresses and spray-on polyurethane foam insulation for buildings are becoming increasingly common. The Ford Motor Company recently announced its intentions to use polyurethane foam made using natural oil polyols in the seats of its Ford Mustang. However, much of the development being performed on the use of natural-oil polyurethane products is limited to, for example, seats, headrests, armrests, soundproofing, and body panels. In other words, these applications make use of the foaming properties of polyurethane, and do not satisfy the need for a non-porous polyurethane solid. What is needed is a durable, non-porous, thermoformable, and colorable polyurethane.